DESCRIPTION: (Applicant's Abstract) This FIRST Award application is a response to PA-95-55 encouraging research on comorbid mental and drug abuse (DA) disorders. An emerging body of evidence indicates that DA is frequently preceded by childhood attention-deficit/hyperactivity disorder (ADHD). Both DA and ADHD are major complex public health problems in and of themselves, and each appears to confer risk for further morbidity. The aim of this proposal is to test hypotheses about the co-occurrence of ADHD and DA in adults and in their high-risk offspring. The proposed work applies the expertise derived from the PI's K20 Career Development Award, which has focused on the developmental link between substance use disorders and child psychiatric disorders, to the first phase in a project aimed at identifying meaningful risk and protective factors for DA in childhood and adolescence when it co-occurs with ADHD. Because ADHD is a common disorder, this study will focus on a highly prevalent subtype of DA that causes considerable psychiatric and social morbidity. In order to test our hypotheses in a manner that will be maximally informative to the literature regarding risk factors for DA, several sampling and design features are used to create an innovative research strategy. A key feature of our sampling frame is that it begins by selecting samples of ADHD and non-ADHD adults with and without DA. Thus, the drug abusers in our sample will not have been selected for clinical referral for their DA. Because most drug abusers are not treatment seekers, and many show an episodic or remitting course of abuse, our sampling frame will increase the generalizability of our results. Another feature of the proposed work is the implementation of a retrospective, concurrent, prospective design: 1) By studying adults, we use a retrospective design to define risk factors from their childhood that are retrospectively associated with DA in adulthood; 2) By examining their children who have not passed through the age at risk for DA, we can establish a profile of factors that distinguish high-risk children from control children; and 3) By following these children who are at high risk for both ADHD and DA, we can determine if these retrospectively and concurrently defined factors are predictive of DA in a prospective study. Within the context of a family study, we will also be able to test hypotheses about familial links between ADHD and DA. Given the high prevalence of ADHD, its related comorbid disorders, its frequent persistence into adulthood, and the high risk it presents to offspring, the proposed study may enable the identification of a large, homogeneous subgroup of children at risk for DA. Moreover, since ADHD is treatable, this high-risk group may be amenable to early intervention and prevention interventions. Thus, the research, approach, and goals of this FIRST Award application are consistent with those underscored in the PA and by the Institute of Medicine as being of highest research priority.